Recirculating ventilating hood

ABSTRACT

A baking and broiling oven is provided with a recirculating ventilating hood having a spring-mounted motor-blower unit. A thin, flat filter box of large area is attached to the underside of the motor-blower unit and carried thereby so as to have a low noise level and high air flow at relatively slow speeds; hence, high efficiency of air filtration.

United States Patent White Jan. 14, 1975 RECIRCULATING VENTILATING HOOD 3,322,111 5/1967 Simpson et al 126/21 R [751 Inventor James White, Louisville, 13312;; $111331 5212;331:1313;......1:::::;'a'8?? 1i l? [73] Assignee: General Electric Company,

Loulsvlue Primary Examiner-Edward G. Favors [22] Filed: Feb. 25, 1974 [21] Appl. No.: 445,449 57] ABSTRACT 52 U.S. c1. 98/115 K, 126/273 A, 126/299 B A Pakmg l a latmg ventllatlng hood having a sprmg-mounted mo- [51] Int. Cl. F24c 15/20 topblower unit A thin flat filter box of large area is [58] Field of Search 126/21 R, 21 A, 273 A,

attached to the unders1de of the motor-blower urut 126/299 B, 98/115 K, 115 R and earned thereby so as to have a low no1se level and 56] References Cited high air flow at relatively slow speeds; hence, high effic1ency of an filtratlon. UNITED STATES PATENTS 2,886,124 5/1959 Scharmer 126/299 X 5 Claims, 3 Drawing Figures PATENIEDJAH 1 4197s SHEET 1 UF 2 RECIRCULATING VENTILATING HOOD BACKGROUND OF THE INVENTION Ventilating hoods are commonly installed over kitchen ranges and cooktops or assembled directly on built-in wall ovens or eye-level ovens of free-standing ranges. In all instances they handle grease, odors and vapor-laden hot air formed during various cooking op -erations so that the air should first be filtered before reaching the motor-blower unit and being vented to the outside of the kitchen or returned to the kitchen in a recirculating manner.

The present invention relates to a recirculating ventilating hood which is not vented to the outside of the kitchen, but instead returns the filtered air to the kitchen atmosphere. The majority of kitchen ventilating hoods are vented to the outside and this disposes of the filtered air. One disadvantage of a vented hood is that it usually requires special carpentry work and sheet metal duct work to carry the exhaust air to the outside of the kitchen; hence, vented hoods add additional cost to the installation of the kitchen range or oven. Another disadvantage is that sometimes the loca tion of the range or oven is such that it is not feasible to install a vent duct through the wall or through the ceiling of the kitchen. Such vented hoods are taught in the three related patents of Donald L. Cole, U.S. Pat. Nos. 3,292,523, 3,292,524, and 3,327,610, all of which are assigned to the assignee of the present invention.

Oneknown manner of converting a vented hood to a recirculating hood is to install a filter box on the top of the vented hood, which filter box is downstream of the motor-blower unit, and then returning to the filtered air to the kitchen atmosphere. This is taught in the Bandlow U.S. Pat. No. 3,075,335.

The principal object of the present invention is to provide a kitchen ventilating hood with a large recirculating filter box that is installed within the hood housing and suspended below the motor-blower unit so as to cut down on the noise level of the hood assembly.

A further object of the present invention is to provide a recirculating ventilating hood with a filter box construction of the largest possible size that takes up the least space within the hood housing so as to have a large volume air flow at a relatively low velocity, as well as low operating temperatures for both the motor and the filter mediums.

SUMMARY OF THE INVENTION The present invention, in accordance with one form thereof, relates to a recirculating ventilating hood that is adapted to be mounted directly on the top of an oven. The hood includes a spring-mounted motorblower unit suspended from the top portion of the hood housing, and there is a large filter box attached to the underside of the motor-blower unit and carried thereby. A front wall of the hood housing includes an air inlet opening and a clean air outlet opening. Filter means are installed in the filter box so as to handle a large volume of air at a relatively low velocity and at a relatively low noise level andat low operating temperatures of the filter medium as well as of the motor for ease in service and improved efficiency without any increase in the overall size of the hood housing.

BRIEF DESCRIPTION OF THE DRAWINGS This invention will be better understood from the following description taken in conjunction with the accompanying drawings and its scope will be pointed out in the appended claims.

FIG. 1 is a fragmentary perspective view of an eyelevel oven of an electric range (not shown) with a recirculating ventilating hood according to the present invention, mounted directly on the top of the oven.

FIG. 2 is a fragmentary cross-sectional, side elevational view on an enlarged scale taken generally through the center of the hood and the center of the motor-blower unit.

FIG. 3 is an exploded view of several of the main components of the present invention; for example, the filter box and its various large filters. The filter box is to be fastened to the underside of the motor-blower unit and carried thereby.

DESCRIPTION OF THE PREFERRED EMBODIMENT Turning now to a consideration of the drawings, and in particular to FIG. 1, there is shown an eye-level, electric oven 10 which is of the type found in a double oven range where the eye-level oven is mounted above a cooktop and there is a second oven located beneath the cooktop. The lower portion of such a range is not illustrated here as it is somewhat standard in the range art. This same oven 10 could be a built-in wall oven. This oven is generally of standard construction having a cooking cavity 12, as best seen in FIG. 2, formed by a box-like oven liner l4 and a front-opening access door 16. A blanket of thermal insulation 18, such as fiber glass or the like, surrounds the oven liner for retaining as much of the oven heat as possible within the cooking cavity. The oven door 16 is provided with a viewing window 20 of multiple panes, and this door is also provided with insulation so as to form a thermal barrier for retaining the oven heat. A control panel 22 is located at one side of the oven door 16, and it may contain control components, such as an oven timer, an oven thermostat, and an oven selector switch, as is conventional in this art.

The present invention relates to a recirculating ventilating hood 25 which is shown mounted directly on the top of the oven 10. The hood 25 has a hollow box-like housing 27 of sheet metal construction having the same dimensions in plan view as the top of the oven so that the hood 25 in effect represents a vertical extension of the oven 10. The hood housing 27 has a top wall 29, a rear wall 31, opposite side walls 33 and a front wall 35 with an air inlet opening 37 adjacent the bottom portion of the front wall. The front. wall 35 has a rearwardly extending barrier 36 that cooperates with a motor-blower unit 49. The control switch for the hood is not shown but it would be mounted in the front wall 35 of the hood. A grease filter 39, of aluminum mesh or the like, is assembled over the air inlet opening 37. This grease filter 39 is shown to be taller than the height of the air inlet opening 37. This is due to a parts standardization program. This same grease filter 39 is used in the production model of our vented hood, and we use the same filter in our recirculating hood in order to hold down-the number of different parts in our inventory. It will be understood that only the lower part of the filter 39 which overlies the air inlet opening 37 is effective to filter the air. The upper portion of the filter 39 is ineffective because it bears against the front wall 35 for at least the upper half of the filter. This filter 39 may be inserted at intervals so as to gain full use of the filter medium. This same grease filter 39 may be seen used for the air inlet opening in the three Cole patents which were cited above as part of the prior art. The oven is vented by having an air gap 41 formed between the top of the oven door 16 and the front flange 43 of the top wall of the oven liner 14. This air gap 41 is always open, such that during both baking and broiling operations oven air is allowed to exhaust upwardly through the air gap 41 to an area just in front of the filter 39 and the air inlet opening 37 of the ventilating hood 25. A hinged canopy 45 is assembled over the front wall 35 of the hood housing 27, and it is shown in its closed position in FIG. 2, and in its open position in FIG. 1. This canopy would be moved to its open position during the operation of the motor-blower unit of the hood.

Within the hood housing 27 is mounted a motorblower unit 49 which has a scroll-shaped housing 51, as is best seen in FIG. 3, with an exhaust opening 53. The bottom wall of the scroll housing 51, as seen in FIG. 2, is provided with a circular opening 55 in which is mounted a drive motor 57 by means of a series of four motor straps 59. These motor straps are radially spaced around the motor and attached to the innermost end of the motor bymeans of bolt fasteners 61. The opposite ends of the motor straps 59 are welded as at 63 to the edge of the opening 55 in the bottom wall of the scroll housing. This drive motor 57 has a vertical shaft 65 on which is mounted a blower wheel 67 having a plurality of vertical vanes 69.

This motor-blower unit 49 is connected to the underside of the top wall 29 of the hood housing 27 by a spring mounting means that is taught in the Cole U.S. Pat. No. 3,327,610. As seen in FIG. 3, a hanger bar 71 is attached to the top wall of the scroll housing 51, and it overhangs the opposite sides of the scroll housing. This hanger bar 71 is of hat-shaped, transverse crosssection. Cooperating with this hanger bar 71 is a stationary supporting bar 73, as seen in FIG. 2, which is shown of generally the same hat-shaped, transverse cross-section as for the hanger bar, and extending for substantially the same distance as the length of the hanger bar. This supporting bar is turned face up and preferably welded to the underside of the top wall of the hood housing 27. Connections must be provided between the hanger bar 71 and the overlying supporting bar 73, and this is afforded by a pair of shouldered bolts 75, one at each end of the hanger bar 71, which may be quickly connected and disconnected from the supporting bar through suitable slot means in the front of the supporting bar, as is best explained in the aforementioned Cole U.S. Pat. No. 3,327,610. The midsection of each bolt 75 is surrounded by a coiled spring 77 on which the hanger bar 71 is supported to give a spring support for the motor-blower unit 49.

It is desirable that the motor-blower unit 49 be easily removable from the hood housing 27 by first removing the canopy 45 in the front wall 35 of the housing by removing the fastening screws 80 that attach the front wall in place. Then by grasping the two hanger bolts 75 they may be released from the supporting bar 73 and the entire motor-blower assembly may slowly be withdrawn from the hood housing 27.

In order to have a satisfactory recirculating ventilating hood it is necessary to have suitable filter mediums to remove the grease, smoke, odors and vapors from the air before it reaches the motor and blower and before the air is returned to the kitchen atmosphere. Preferably, such filter mediums are installed upstream of the blower system so as to protect the motor and blower from the air pollutants.

The present invention incorporates a thin, flat filter box of large expanse, as is best seen in FIG. 3, that is attached to the underside of the motor-blower unit 49 and carried thereby so that the filter box is also spring mounted through the motor-blower unit, thereby being isolated from the hood housing and reducing the noise level of the entire assembly. The nature of the filter box 85 can be best understood from the exploded perspective view of FIG. 3. The filter box 85 has a thin, flat shell of large planar area that is almost as wide as the hood housing 27. It has a top wall 87, a rear wall 89, widely spaced opposite side walls 91, a front wall 93 that is open along its bottom portion, and finally it has an open bottom wall. An enlarged motor-receiving opening 95 is formed in the top wall 87 of the filter box shell substantially in the center thereof, and it has an inwardly tapered collar 97 which is adapted to telescope within the inlet opening 55 of the bottom wall of the motor-blower scroll housing 51. Screw openings 98 are formed in the top wall 87 of the filter box for receiving screws (not shown) that are threaded into suitable openings in the bottom wall of the scroll housing 51.

A center brace 99 is located beneath and spaced from the motor-receiving opening 95 and this brace is of wide channel-like form that extends from front to back of the filter box shell. This brace 99 is attached to the underside 100 of the front wall 93 of the shell, as by screw fasteners or the like. The rear wall 89 of the shell has a forwardly turned flange 101 along its bottom edge on which the center brace 99 is seated and fastened as by screw fasteners or the like. Thus, the center brace serves to reinforce the filter box shell and restrict any noise generations due to vibrations set up by the operation of the motor-blower unit. Notice the center brace 99 also has a circular opening 102 for receiving the motor 57 therein.

The preferred embodiment of the present invention has the filter box 85 provided with two pairs of filter mediums, the bottom filter 103 of each pair being a grease filter of fiber glass or the like that also removes smoke particles. There is also a top filter 105 in each pair of filters of activated coconut shell or pecan shell charcoal or the like for absorbing odors and other pollutants. These two pairs of filters 103 and 105 are adapted to be installed in the bottom portion of the filter box 85. Their support is afforded by an inwardly turned flange 107 formed on the bottom edge of each side wall 91, and by an oppositely facing flange 109 formed along the bottom edge of the side of the center brace 99. These two flanges 107 and 109 form rails on which the double filters 103 and 105 are capable of sliding into the filter box beneath the front wall 93 of the filter box shell.

It will be understood from FIG. 2, that the air exits from the oven through the air gap 41 along the top edge of the oven door and across the front of the ventilating hood 25 and through the first grease filter 39 and through the air inlet opening 37 from which it spreads out beneath the entire filter box 85. Due to the suction created by the blower wheel 67 the air is drawn upwardly through the two pairs of filters 103 and 105 into the upper portion of the filter box shell. Then the air is drawn together towards the motor-receiving opening 95 and passes up around the motor 57 and into the blower wheel 67 from which it exits through the exhaust opening 53 of the scroll housing. The upper portion of the front wall 35 of the hood housing has an elongated clean air outlet 115 such that the clean air discharges back into the kitchen at an upward angle so as not to prove uncomfortable to a person standing in front of the oven.

Modifications of this invention will occur to those skilled in this art, therefore it is to be understood that this invention is not limited to the particular embodiments disclosed but that it is intended to cover all modifications which are within the true spirit and scope of this invention as claimed.

I claim:

1. A recirculating ventilating hood for installation on the top of an oven, said hood comprising a hollow housing with at least a top wall, a rear wall, opposite side walls, and a front wall having an air inlet opening, first filter means in said inlet opening, a spring-mounted motor-blower unit suspended from the top wall of the housing and exhausting through a clean air outlet in the said front wall, and a large filter box attached to the un' derside of the motor-blower unit and carried thereby, said filter box having a thin, flat shell of large area with a top wall, a rear wall, widely spaced opposite side walls, and a front wall that is open along its bottom portion, and an enlarged opening in the top wall of the shell, shelf means within the filter box shell at both sides of the said opening for supporting a second filter means in the bottom portion of the filter box shell, whereby the large area of the second filter means allows for a large volume of air flow at a relatively slow speed and a low noise level and relatively low motor and filter means temperatures.

2. A recirculating ventilating hood as recited in claim 1 wherein the said filterbox shell includes a center brace located beneath and spaced from the said opening and connected to both the front wall and rear wall of the shell, said center brace serving as part of the said shelf means for supporting the second filter means.

3. A recirculating ventilating hood as recited in claim 2 wherein when the motor-blower unit is energized, an air flow is set up so that the air enters through the air inlet opening in the front wall of the hood housing and passes through the first filter means, then spreads out beneath the entire filter box and rises up through the second filter means and accumulates near the said opening and passes therethrough and into the blower and finally out the clean air outlet.

4. A recirculating ventilating hood as recited in claim 1 wherein the said front wall of the hood housing is removable from the front so that the said second filter means may be disengaged from the filter box and removed easily through the front of the housing for cleaning and replacement.

5. A recirculating ventilating hood as recited in claim 1 wherein the motor-blower unit has a scroll-shaped housing enclosing a single blower wheel and supporting a drive motor having a vertical shaft that is connected to the blower wheel, the said motor extending down beneath the blower housing and into the said top opening in the filter box. 

1. A recirculating ventilating hood for installation on the top of an oven, said hood comprising a hollow housing with at least a top wall, a rear wall, opposite side walls, and a front wall having an air inlet opening, first filter means in said inlet opening, a spring-mounted motor-blower unit suspended from the top wall of the housing and exhausting through a clean air outlet in the said front wall, and a large filter box attached to the underside of the motor-blower unit and carried theReby, said filter box having a thin, flat shell of large area with a top wall, a rear wall, widely spaced opposite side walls, and a front wall that is open along its bottom portion, and an enlarged opening in the top wall of the shell, shelf means within the filter box shell at both sides of the said opening for supporting a second filter means in the bottom portion of the filter box shell, whereby the large area of the second filter means allows for a large volume of air flow at a relatively slow speed and a low noise level and relatively low motor and filter means temperatures.
 2. A recirculating ventilating hood as recited in claim 1 wherein the said filter box shell includes a center brace located beneath and spaced from the said opening and connected to both the front wall and rear wall of the shell, said center brace serving as part of the said shelf means for supporting the second filter means.
 3. A recirculating ventilating hood as recited in claim 2 wherein when the motor-blower unit is energized, an air flow is set up so that the air enters through the air inlet opening in the front wall of the hood housing and passes through the first filter means, then spreads out beneath the entire filter box and rises up through the second filter means and accumulates near the said opening and passes therethrough and into the blower and finally out the clean air outlet.
 4. A recirculating ventilating hood as recited in claim 1 wherein the said front wall of the hood housing is removable from the front so that the said second filter means may be disengaged from the filter box and removed easily through the front of the housing for cleaning and replacement.
 5. A recirculating ventilating hood as recited in claim 1 wherein the motor-blower unit has a scroll-shaped housing enclosing a single blower wheel and supporting a drive motor having a vertical shaft that is connected to the blower wheel, the said motor extending down beneath the blower housing and into the said top opening in the filter box. 